JPS62246476A - Manufacture of polishing tape - Google Patents

Abstract

PURPOSE:To decrease the degranulation of a polishing material and at the same time improve the even smoothness of a polishing film by preparing liquidization by means of two different treatments called a kneading and attriter dispersion treatments. CONSTITUTION:The liquidization-preparation of a polishing material and a binding material is accomplished, and the polishing liquid generated from this preparation is spread on the flexible support of a polishing tape. This polishing liquid spread on is dried and the polishing tape is manufacture. On this occasion, this prepared liquid included at least some of the polishing material and at least some of the binding material which have undergone a kneading and attriter dispersion treatments. By this kneading treatment, the affinities of the polishing material and the binding material are improved and their bonding force is strengthened, so that the degranulation of the polishing material off a polishing layer can be prevented. Moreover, by the attriter dispersion treatment, the polishing material is minutely and uniformly dispersed in the binding material up to primary particles, so that the even smoothness of a polishing film can be improved, and the polishing finish of a magnetic head by the polishing tape is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a polishing tape for polishing a magnetic head, and more specifically to a method for preparing a polishing liquid to be applied onto a flexible support of the polishing tape. It is related to.

(Prior art) A polishing solution is prepared by preparing an abrasive and a binder (hereinafter referred to as a binder), etc., and this polishing solution is applied to a long flexible support. A method of producing an abrasive tape by drying is known.

In this method of manufacturing an abrasive tape, it is possible to reduce shedding of the abrasive in the finished abrasive tape, and to reduce the polishing process. The challenge is to improve the flat W1 properties of the painted pattern and prevent it from rusting.

Appropriate oitllL to solve such problems
It is necessary to produce a liquid, and for this purpose it is necessary to prepare the liquid by appropriate processing. In other words, in order to prevent the abrasive from falling off, it is necessary to increase the bonding strength between the abrasive and the binder, and in order to improve the smoothness of the abrasive coating film, the abrasive must be kept in the form of primary particles. It is necessary to uniformly disperse the resin in the binder, and a process that can solve the above problem should be carried out in consideration of this point.

However, the bonding strength between the abrasive and the binder can be sufficiently improved in a short period of time by a well-known solution preparation method using a ball mill (Japanese Patent Application Laid-Open No. 55-1299274, cleaning tape: Hitachi Maxell). It is also difficult to sufficiently finely disperse the abrasive down to the primary particles, and the above problems cannot be said to have been solved. In addition, a liquid preparation method using a roll mill, which is also well known in the past (Japanese Patent Publication No. 53-44714, Polishing Tape:
It is difficult to sufficiently improve the bonding force between the abrasive and the binder using Deutsche Pigment Kogyo IA), and it is extremely difficult to finely disperse the abrasive down to the primary particles. I couldn't do that.

(Object of the Invention) The present invention has been made in view of the above circumstances, and it is possible to reduce shedding of abrasive and improve the smoothness of the grinding srs. The object of the present invention is to provide a method for producing an abrasive tape.

(Structure of the Invention) The method for manufacturing an abrasive tape of the present invention is characterized in that at least a part of the abrasive and a part of the binder are subjected to liquid preparation including at least a kneading process and an attritor dispersion process. .

here,? The type, shape J3, and size of the l11M agent may be selected appropriately depending on the purpose, and are not particularly limited.

In addition, the binder may be of type 14 as long as it can adhere the abrasive onto the support, but as long as it has polarity and contributes to the dispersion of the abrasive and improves the IQ. More preferred. Particularly preferred are nitrocellulose, water All, and a vinyl chloride-vinyl acetate copolymer having a carboxyl group.

Next, the above crosstalk processing will be explained. Here, crosstalk refers to kneading.
Examples of means for cross-talk include a pressure kneader (pressure double-arm kneader), an open kneader (double-arm kneader), and a three-roll mill. Among these, the pressure kneader and the open kneader are capable of strongly mixing the polishing liquid in a cake-like manner, and are also excellent in workability. Note that a pressure kneader is better than an open kneader in terms of strong crosstalk. Further, the above-mentioned kneading needs to be done vigorously, and it is preferable to knead the polishing liquid in a rice cake-like state, and it is necessary to knead it at a high viscosity of at least 100 voices or more.

Next, the above-mentioned attritor distribution processing will be explained. In general, an attritor consists of a stationary cylindrical tank filled with balls or pebbles as a dispersion medium, and a hemil base (pigment + vehicle slurry) filled in this tank and placed in the center of the tank. Several arms installed at right angles to the vertical rotation axis and the center axis are rotated, and these rotating arms are applied to the above dispersion media. ! A dispersion device that applies continuous shear stress to disperse pigments into a mill-based vehicle. The above-mentioned attritor dispersion process is a fractional process performed using this attritor, and is a process that can finely disperse the abrasive down to the primary particles. The dispersion time is, for example, 2 to 48 hours, preferably 6 to 24 hours. Furthermore, specific examples of the above-mentioned dispersion media include still beads, alumina beads, zirconia beads, glass beads, and the like. Also,
The ratio of the apparent dispersion media volume to the total volume in the attritor tank (apparent dispersion media volume MA/total volume), that is, the apparent volume ratio is, for example, 100/100 to 1.
00/・goo, preferably 100/ TOO ~ 100
/ 500. Note that the above-mentioned apparent volume of the dispersion media is the product of the total height of the dispersion media deposited in the tank by the bottom area of the tank.

The viscosity of the polishing liquid at this time is, for example, 10 to 300 voids, preferably 20 to 200 voids, and most preferably 30 to 150 voids.

Also, the crosstalk area]! l! J3 and attritor dispersion processing do not necessarily need to be performed on all the fingers of the abrasive and binder, but may be performed on only a portion of each finger. Part of the abrasive is 10% or more of the total layer of the abrasive, preferably 20% or more of the total layer of the abrasive.
% or more. Further, a part of the binder refers to 10% or more of the total binder, preferably 20% or more, and more preferably 30% or more.

Further, the liquid abrasive material to be prepared does not necessarily mean that it consists only of an abrasive and a binder, but may also contain additives such as a dispersant and a lubricant.

Further, the above-mentioned liquid preparation does not necessarily mean that it consists only of crosstalk treatment and attritor dispersion treatment, but may also include various other appropriate treatments. Further, particularly preferably, the kneading is performed before the attritor dispersion.

The above-mentioned attritor, pressure kneader, open kneader, ball mill, and three-roll mill are not shown below but are described in detail in the literature.

"Mixing and kneading technology" (by Yano, 2nd Nikkan Kogyo Shimbun).

8,120 units issued in 1981), [paint F
! owPigsent Disqersion ](
by T. C. Patton, 1 interscence
Publishers, October 1968), "Introduction to Dispersion Technology" (written by Koishi and Tsukutani, 2 Nikkan Kogyo Shimbun, published January 20, 1972), "Cross-wire Technology" (written by Hashimoto, Industrial Technology Center, 1977) Published on October 5, 2017) etc.

In the present invention, the abrasive tape broadly includes not only so-called tape-shaped polishing tapes but also disc-shaped and sheet-shaped polishing tapes.

(Effect of R-light) According to the method for manufacturing an abrasive tape of the present invention, liquid preparation is performed by two different processes: kneading treatment and attritor dispersion treatment, and multiple problems that have conventionally occurred can be solved for each problem. In addition to addressing these issues individually, the synergistic effects brought about by the image processing are used to address these issues as a whole.

That is, the kneading process mixes the R111 abrasive and the binder in a high viscosity state, improving the affinity between the two and strengthening the bonding force between the two, thereby preventing the abrasive from falling off from the RTL polishing layer. can. This can improve the durability of the polishing coating.

In addition, the attritor dispersion process uniformly finely disperses the abrasive down to the primary particles in the binder, and since there are no areas where abrasive particles are aggregated in the abrasive solution, the smoothness of the abrasive film improves, making this abrasive tape The final polishing properties of the magnetic head using the magnetic head are improved. That is, there is less risk of scratches on the surface of the magnetic head, and the surface smoothness of the magnetic head can be improved.

In addition, in terms of preventing shedding of abrasives, the attritor dispersion process finely disperses the abrasives and increases the bonding force between the rIII abrasive and the binder, so the crosstalk treatment is more effective than when performed alone. It can be made certain.

Furthermore, in terms of improving the smoothness of the abrasive coating film, when performing the attritor dispersion treatment after the kneading treatment (Yo, after the abrasive has been dispersed to some extent by the kneading process, the attritor dispersion treatment Since the fine dispersion of the attritor can be performed, a highly smooth surface can be formed in a shorter time than when the attritor dispersion process is performed alone.

(Example) Examples of the present invention will be described below.

- Example 1 A polishing liquid having the composition shown below was kneaded for 30 minutes using an open kneader, and after becoming cake-like, it was further kneaded for 30 minutes. Then, add medylethyl ketone (
100 parts) was added to prepare polishing liquid B as a liquid (60 voids). Next, this polishing liquid B was put into an attritor and subjected to an attritor dispersion treatment for 18 hours to produce a polishing liquid C. This polishing liquid C had a liquid viscosity of 10 voices. Steel peas (φ 1/4 inch) were used as the dispersion media of the attritor, and the apparent volume ratio expressed by the total volume of the dispersion media was set to 100/120. Thereafter, the polishing liquid C was filtered through a 3μ filter, applied to a 12μ thick polyester film to a thickness of 8μ (dry thickness), and dried to form a coating film. Thereafter, one portion of the polyester film with this coating formed thereon was cut into 2-inch width pieces, and it was cut into pieces with a width of 2 inches.
+Made polishing tape 1. In addition, the composition materials and the content ratio of the above-mentioned methyl ethyl ketone to the 1i411 liquid are based on the solid content composition. Further, 2]-rocell[1-su as a binder is dissolved in advance in methyl ethyl ketone as a solvent.

Composition of polishing liquid A rIPl@ agent (X AL20s (size φo, 3
μ) 300 parts Nitrocellulose 5
0 parts methyl ethyl ketone ・・・・・・
200 parts lecithin (dispersing agent)
・・1.5 parts・Example 2 A polishing liquid having the J composition shown below was mixed with a pressure kneader for 30 minutes.
The mixture was kneaded for a minute, and after the mixture became cake-like, it was further kneaded for 1 hour. Thereafter, this kneaded material was further kneaded while blowing dry air, so that it was crushed into pieces with a diameter of about a few σ. Next, this crushed material was placed in an attritor together with a polishing liquid E having the composition shown below, and subjected to attritor dispersion treatment for 24 hours to produce a polishing liquid F.

rJl polishing fluid F had a viscosity of 85 poise. Steel peas (φ1/4
inch), and the apparent volume ratio expressed by the total volume of the dispersion media was 100/12G. Next, polishing liquid F was filtered through a 3μ filter, and then put into a stirrer together with polishing liquid G having the composition shown below.
I made it. Polishing liquid 1 had a liquid viscosity of 80 voices. After this,? The ilI polishing all was filtered through a 3μ filter, applied to a 12μ thick polyester film to a thickness of 8μ (dry thickness), and dried to form a coating film. After that, a 172 inch thick polyester film on which this coating was formed was
I cut it into p and made rtlJ ffi Dave 2.

Composition of polishing liquid Abrasive agent γ-Fezo3 (Size 1.0μ×0.1μ×0.1μ)・・・・・・
200 parts Vinyl chloride-l vinyl acetate-vinyl alcohol copolymer 80 parts Amyl stearate 2.0
Part methyl ethyl ketone...1
00 parts vinegar @ n-butyl...
・Composition of 320FB polishing liquid E Polishing agent Cr203 (Size φ 0.3μ)...
・ 150 parts carbon black ・・
...30 parts methyl ethyl ketone
...100i cyclohexanone
...3507! IA leic acid ・
...3 parts silicone oil ...0.2 parts fluorine oil ...1 part liquid paraffin ...1 part butyl stearate ... 1 part surfactant 2 parts Composition of polishing liquid G Terminated isocyanate prepolymer (curing agent)...
35 parts Comparative Example 1 Methyl ethyl ketone (10 parts) was added to the polishing liquid shown in Example 1.
0 parts) in a ball mill and subjected to dispersion treatment for 96 hours. Steel peas (φ
3/4 inch) was used.

This dispersion-treated liquid was filtered through a 3μ filter, and the 12μ
It was coated on a thick polyester film to a thickness of 8 μm (dry thickness) and dried to form a coating film. Then this tl! The polyester film on which the film was formed was cut into pieces each having a width of 2 inches to prepare polishing tape 3.

・Comparative Example 2 Methyl ethyl ketone (10
(0 parts or more) were kneaded in a three-roll mill to obtain 1 g of a low-viscosity (5 voids) polishing slurry. Note that the amount of added solvent was adjusted as appropriate so that the viscosity remained at the same level even during crosstalk. Next, this polishing slurry was applied to a 12μ thick polyester film to a thickness of 8μ (dry thickness) using a 5μ filter (unfortunately, a 3μ filter has poor filtration properties) and dried to form a coating film. Thereafter, this polyester film on which Q was formed was cut into pieces of 2 inches + i to prepare polishing tape 4.

Number of fallen rIIIe particles and surface roughness R of polishing tapes 1 to 4 made in Example 1.2 and Comparative Examples 1 and 2
a) was measured and the results are shown in the table below.

The number of dropped rIll abrasive particles was determined by observing the surface of the abrasive tape after grinding the ferrite head using an electron microscope (magnification: 5,000 times), counting the number of dropped abrasive particles by the number of dents, and expressing the result as a relative value. Furthermore, the surface roughness (Ra) is the average roughness measured at the center rA of the surface of the coating film. The cutoff value was 0.8allll, the stylus radius was 2μ, and the stylus 1 speed was 0.3fi/Sec.

As is clear from the above table, according to Examples 1 and 2, it is possible to prevent the abrasive from falling off and to make the surface of the abrasive coating film of the tape smooth.

Note that the embodiments of the present invention are not limited to those described above, and there are various embodiments that can achieve the object of the present invention.

Claims (1)

[Claims] A polishing tape is produced by preparing a solution of an abrasive and a binder, applying the abrasive solution produced by this solution onto a flexible support, and drying the applied abrasive solution. In the method of manufacturing an abrasive tape, the liquid preparation includes a kneading treatment and an attritor dispersion treatment performed on at least a part of the abrasive and at least a part of the binder. Method.